I’ve seen quite a few toys in the past two years but Wedgits are actually something I’d recommend. My buddy Jer brought them for our son and he’s been building towers and knocking them over with reckless abandon.
They are essentially symmetrical square rings (is there a better geometrical term?) that stack and lock without force. Because they fit inside each other you can actually build solid objects with a little planning.
Granted, these aren’t quite as fun as Lego, at least in terms of possible shapes you can build, but they’re big enough for littler hands and won’t hurt as much when you step on them. The introductory set costs $22 and the soft set for the wee ones cost $44. Best of all the larger sets include a large green base.